In recent years, in the electronic device manufacturing field represented by the integrated circuit device manufacture, demands for high integration of a device are increasing, and for that reason, a photolithography technology for the formation of a fine pattern is considered to be needed.
As techniques for microfabrication, in general, wavelength shortening of an exposure light source is carried out. Specifically, though an ultraviolet ray represented by a g-ray or an i-ray have been conventionally used, at present, the mass production of semiconductors using a KrF excimer laser or an ArF excimer layer is commenced. Also, the manufacture of semiconductors using an F2 excimer laser, an electron beam, EUV (extreme ultraviolet ray), an X-ray or the like each having a shorter wavelength than such an excimer laser is studied.
A resist material is required to have lithographic characteristics such as sensitivity to such an exposure light source, resolution capable of reproducing a pattern with a fine dimension, etc. As the resist material satisfying such a requirement, chemical amplification type resists composed of an acid dissociable functional group-containing polymer compound and a compound capable of generating an acid upon irradiation with radiations (hereinafter referred to as “exposure”) (the latter compound will be hereinafter referred to as “photo acid generator”) are used.
This acid dissociable functional group-containing polymer compound is based on a structure in which a part of an alkali easily soluble site of an alkali soluble polymer compound is protected by an appropriate acid dissociable functional group, and the selection of such an acid dissociable functional group is very important in view of regulating a function as a photoresist composition.
For example, there are known photoresist compositions containing, as a component, a polymer compound obtaining by polymerizing a raw material containing an adamantyl group-containing acrylate as the acid dissociable functional group-containing polymer compound (see Non-Patent Document 1 and Patent Document 1); and photoresist compositions containing, as a component, a polymer compound containing an acrylate having a lactone ring or the like as a constituent unit (see Patent Document 2).
Furthermore, there are proposed photoresist compositions containing, as a component, a polymer compound containing a norbornane lactone-containing constituent unit and having high etching resistance and enhanced adhesion to substrate (see Patent Document 3). Also, there are proposed photoresist compositions containing, as a component, a polymer compound containing a constituent unit in which a connecting group is introduced, and norbornane lactone is present far from a main chain thereof (see Patent Documents 4 and 5).